WATER MICROBIOLOGY AND FERMENTATION

Question 1

Essential to all organisms

Answer 1

water

Question 2

WATER-BORNE DISEASES
Bacterial

Answer 2

● Leptospirosis (Leptospira)
● Typhoid (S. enterica serotype typhi)
● Paratyphoid (S. enterica serotype paratyphi)
● Cholera (Vibrio cholerae)
● Bacillary Dysentery (E. coli, Shigella, Campylobacter, Salmonella)

Question 3

WATER-BORNE DISEASES
Viral

Answer 3

● Viral Hepatitis (Hepatitis virus A and E)
● Poliomyelitis (poliovirus)
● Infant diarrhea (Rotavirus)
● Gastroenteritis and Traveler’s Diarrhea due to Norovirus

Question 4

WATER-BORNE DISEASES
Protozoal and Parasitic

Answer 4

● Amoebiasis (Entamoeba histolytica)
● Giardiasis (Giardia lamblia)
● Schistosomiasis (Schistosoma)
● Roundworms, Whipworms (helminths)

Question 5

microorganisms whose presence also indicates the probable presence of pathogenic microorganisms.

Answer 5

Indicator organisms

Question 6

Example of indicator organisms (particularly used in water microbiology assessments) are

Answer 6

coliforms

Question 7

Indicator of fecal/sewage contamination in food or water, thus indicating possible presence pathogenic bacteria.

Answer 7

coliforms

Question 8

coliform characteristics

Answer 8

Rod-shaped (bacilli)
facultative anaerobe
non-spore forming
lactose-fermenting
gram-negative bacteria

Question 9

why do we use indicator organisms and not tets the pathogen directly?

Answer 9

Indicator organisms are used instead of directly testing for pathogens because it’s impractical to test for every pathogen in every water sample

the main pathogen is also very small in numbers

Question 10

agar used in water quality tests to distinguish coliforms and fecal coliforms that signal possible pathogenic microorganism contamination in water samples

inihibts the growth of most gram-positive bacteria

differentiates bacteria that ferment lactose

Answer 10

Eosin-Methylene Blue (EMB) Agar

Question 11

● Based on statistical estimation using Most Probable Number of MPN
● MPN estimates the concentration of viable mcgs in a sample
● Sub-samples are inoculated in a series of tubes

Answer 11

Multiple Tube Fermentation Technique
(MTFT)

Question 12

Multiple Tube Fermentation Technique
(MTFT) Typically composed of 3 stages

Answer 12

presumptive, confirmed, and
completed

Question 13

Multiple Tube Fermentation Technique
(MTFT)

Answer 13

Stage 1: Presumptive test in Lactose Broth with Durham tube
After incubation: Check for yellowing/gas production in the tubes is (+) for presumptive test

Stage 2: Confirmed Test using EMBA
After incubation: Check for dark colored colonies or green metallic sheen colonies is (+) for confirmed test

Stage 3: Completed Test via IMViC and Microscopy
After Gram Stain: Look for gram negative, non-spore forming rods is positive for Completed Test
After IMViC: Indole (+), Methyl Red (+), Voges Proskauer (-), Citrate (-) is positive for E. coli

Question 14

Test if tryptophan is converted to indole

Answer 14

Indole Test

Question 15

Indole Test
Indicator
mechanism
positive, negative result

Answer 15

(+) Red ring is observed when Kovac’s reagent is reacts with indole.

Question 16

Detects lower pH due to fermentation of glucose

Answer 16

Methyl Red

Question 17

Methyl Red
Indicator
mechanism
positive, negative result

Answer 17

Methyl red indicator
Yellow to red if acidic products are produced.

Question 18

● Test if mcg uses citrate

Answer 18

Citrate Utilization Test

Question 19

Citrate Utilization Test
Indicator
mechanism
positive, negative result

Answer 19

● Citrate permease
● If mcg uses citrate NH4 salts are converted to NH3 which rises the pH
● Bromothymol blue (green to blue)

Question 20

● To check acetoin production from glucose fermentation

Answer 20

Voges Proskauer

Question 21

Voges Proskauer
Indicator
mechanism
positive, negative result

Answer 21

● In the presence of oxygen, alkali and naphthol, acetoin is converted to diacetyl w/c condenses with guanidine from peptone w/c produces a pinkish polymer

Question 22

IMViC test stands for

Answer 22

Indole Test
Methyl Red
Voges Proskauer
Citrate Utilization Test

Question 23

a statistical method used to estimate the viable numbers of bacteria in a sample by inoculating broth in 10-fold dilutions

MTFT results are interpreted using this Table

Answer 23

Most Probable Number (MPN) Table

Question 24

● Determine microbial load of sample by calculating colony forming units per unit of the sample (cfu/g or cfu/ml)
● Done using Plate Count Agar (PCA)
● Good quality water should have <100 cfu/mL
● HPC indicates efficiency of water treatment (chlorination, filtration, sedimentation etc.)

Answer 24

HETEROTROPHIC PLATE COUNT

Question 25

Series of sequential dilution used to reduce dense cultures to obtain usable (countable) concentration This is performed in conjunction with plating e.g., spread or pour plating to estimate the microbial load in a sample

Answer 25

Serial Dilution

Question 26

calculate colony forming units per unit of sample:

Answer 26

Cfu/ml = (no. of colonies*/amount inoculum plated) x dilution factor if done in duplicates, use average no. of colonies

Question 27

colonies are the usable counts

Answer 27

30-300

Question 28

<30 colonies

Answer 28

TFTC

Question 29

>300 colonies

Answer 29

TNTC

Question 30

Inoculum plated spread plate

Answer 30

0.1 mL

Question 31

Inoculum plated pour plate

Answer 31

1.0 mL

Question 32

count the number of colonies of microorganisms that have grown on an agar plate prepared from a sample

Answer 32

quebec colony counter

Question 33

Metabolic pathway of oxidation-reduction to produce energy. Performed by heterotrophic organisms anaerobically (in absence of oxygen). In this process, there is no net oxidation of the fuel.

Answer 33

FERMENTATION

Question 34

FERMENTATION Common fuel

Answer 34

sugars, fatty acids, amino acids, purines and pyrimidines.

Question 35

types of fermentation

Answer 35

Lactic Acid or Homolactic Fermentation Ethanol or Alcohol Fermentation

Question 36

one molecule of glucose is ultimately converted to two molecules of lactic acid.

Answer 36

Lactic Acid or Homolactic Fermentation

Question 37

one molecule of glucose yields carbon dioxide and ethanol in addition to lactic acid

Answer 37

Heterolactic fermentation

Question 38

WINE MAKING Preparation of Fruit Mash

Answer 38

1.0 kg fruit Osterize and liquify in a blender in 250 ml of water Fill the fruit mash with water up to 2 Liters in a large beaker Add 500 g sugar and stir to dissolve Test pH and adjust it to 4.0-4.7. For highly acidic mash, adjust using CaCO3 Heat at 65 °C for 30 minutes (pasteurize). Cool and transfer to a demijohn gallon

Question 39

WINE MAKING Fermentation Proper

Answer 39

Add a teaspoon yeast (Saccharomyces cerevisiae) Set-up the demijohn and the limewater trap accordingly Ferment for 1 week and or until no bubbles are seen in the limewater trap

Question 40

WINE MAKING Wine Harvesting

Answer 40

After fermentation, filter the mash through a cheesecloth Add one beaten egg in the filtrate Pasteurize at 65 °C for 30 minutes the mixture then decant in sterile bottles.

Question 41

are large vessels for fermenting wine, cider and mead. They are often made from thick glass

Answer 41

demijohn gallon

Question 42

optimum ph for wine mash

Answer 42

4.0-4.7

Question 43

trap for wine demijohn, to determine whether carbon dioxide was produced. When this reacts with CO2 it becomes milky.

Answer 43

Limewater Trap Ca (OH)2

Question 44

is a sour milk product attributed to the presence of lactic acid produced by bacteria that underwent fermentation

Answer 44

Yoghurt

Question 45

Commonly used bacteria in yogurt production:

Answer 45

● Streptococcus thermophilus ● Lactobacillus bulgaricus

Question 46

YOGURT MAKING

Answer 46

Put the 1L of Fresh milk in large beaker Add Skim milk powder then stir Heat the mixture in a water bath at 90 °C for 10 minutes Chill the mixture in an ice bath Add the starter culture Incubate at 43-46 °C for at least 4 hours or until clotting is observed.

Question 47

brings the acidity to the desired level.

Answer 47

Tartaric, citric or malic acid

Question 48

neutralize excess acidity

Answer 48

Potassium tartrate or calcium carbonate

Question 49

enzymes that clears the wine

Answer 49

Tarnin and pectolytic

Question 50

produces fizz or effervescence (from secondary fermentation)

Answer 50

Invert or cane sugar

Question 51

arrests the fermentation in the making of appetizer and dessert wines.

Answer 51

Brandy

Question 52

wines that contains low sugar

Answer 52

Dry table wines

Question 53

Are found in table and sparkling wines

Answer 53

EtOH (18.5%)

Question 54

found at 10-175 mg/100mL of wines.

Answer 54

Higher alcohols e.g., isoamyl and butyl-OH

Question 55

Acids such as ________ are also produced but in excess this can lead to spoilage of wine.

Answer 55

formic, acetic and propionic

Question 56

Table wines typically contain 0.5 to 1.0%

Answer 56

titratable acidity

Question 57

most desirable level of titratable acidity

Answer 57

0.65%

Question 58

Volatile fatty acids (VFAs) are produced through heterolactic fermentation

Answer 58

true

Question 59

Volatile fatty acids (VFAs)

Answer 59

acetic, propionic, and butyric acids

Question 60

Enzyme and reagent in indole test

Answer 60

tryptophanase enzyme Kovac reagent